Rosalia Spierer was born into the family of a Jewish country-estate manager in the city of Galați in eastern Romania (then in the Romanian Old Kingdom). In 1925, she graduated from the Superior School of Architecture in Bucharest. Upon struggling to find employment in Bucharest, in 1932 she moved to Bălți, Romania’s second largest city, where she–as the only trained architect–became employed at the local municipality. In 1934, Spierer led a number of reconstructions and adaptations of former private villas for public functions, and designed two modernist school buildings (one of those still exists today as the rector’s office of Alecu Russo State University).

In 1940, the region was occupied by the Soviet Union and became a part of Moldovan Soviet Socialist Republic. During the Second World War, Spierer was evacuated to the Saratov region in Russia and later to the city of Fergana in Uzbekistan. In 1944, she returned to Moldova, settling in Chişinău. Based at Molgiprostroy between then and her retirement in 1972, she became a leading architect in the republic, with her work represented at the First Exhibition of Soviet Architects. During the post-war years, she worked on rebuilding and reconstructing surviving buildings, including those of the Zhdanov Library (formerly the Swiss Hotel), of the Moldovan MInistry of Finance, and several buildings of Chişinău Polytechnic Institute, turning to the design of high-rise concrete buildings towards the end of her career.